Telephone system



Sept. 2, 1941. R. F. MALLINA TELEPHONE'SYSTEM Filed Feb. 2, 1940 2 sheets-sheet 1 /NvE/vroR R. E MALL/NA Sept. '2, 1941. R. F'. MALLINA TELEPHONE SYSTEM lF'iled Feb. 2, 1940 2 Sheets-Sheet 2 /NVENTOR R. E MA L L /NA Patented Sept. 2, 11941 TELEPHONE SYSTEM Rudolph F. Mallina, Hastings on Hudson, N. Y.,

assigner to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application February Z, 194.0, Serial No. 316,867 Y 8 Claims.

This invention relates to signaling devices and particuiarly to impulse dials for use in telephone systems.

The objects are to combine with the usual function of an impulse transmitter or dial the added function of identifying the calling subscribers on party lines, and to simplify and otherwise improve the structure of these devices.

Heretofore party line systems have been provided in which the plucking of a reed at a subscribers station causes electrical oscillations corresponding to the natural frequency of the plucked reed to be produced and transmitted over the line and arrangements have been provided at the central office for identifying a calling party by such oscillations. In these systems the reed may act when plucked in an electromagnetic field to cause said eld to set up corresponding oscillations in a coil surrounding the reed and connected to the Vline for the transmission of said oscillations to the central oliice and the plucking of the reed may be controlled by theoperation of the dial.

It is a feature of the present invention to improve such devices having a reed in the magnetic field surrounded by a coil, by providing means for tensioning the reed and locking it in the tensioned position when the dial is moved from normal and tripping the reed to permit it to vibrate at its natural frequency when the dial is returned to normal after the dial pulses have been produced.

This invention has been illustrated in the accompanying drawings in which:

Fig. 1 shows the side View of a standard dial structure in which the invention has been incorporated;

Fig. 2 shows a rear view of this dial;

Fig` 3 shows a bottom View of this dial;

Figs. 4 and 5 show various positions of the applicants mechanism during the operation thereof as applied to this dial structure viewed from the rear of the dial structure; while Fig. 6 shows a perspective View of the applicants invention as applicable to a standard dial.

Fig. 7 shows the applicants invention as applied to a telephone circuit shown in diagrammatic form.

Referring now to the drawings, I indicates the housing of a standard dial and 2 the nger plate that may be rotated to operate the mechanism in the housing I to produce and send digits by the interrupter springs, generally indicated by the numeral 3. The standard mechanism for transmitting dial pulses has not been shown in great (o1. ris-.90)

'On the back of the housing I is located the mechanism incorporating the applicants invention. This mechanism consists of the main bracket 5 having downwardly projecting lugs 6,-1 and 8 which secure the bracket 5 to the housing I by means of screws as shown. On a pin 9 on bracket 5 is rotatably mounted a lever II. Between the U-shaped projection I2 of the bracket 5 and the main portion thereof is mounted a trigger I3-lon the pin I4. This trigger I3 is held in anormal position by `a spring I5 connected at one end to kthe trigger and at the other end to a pin I6 mounted on the main portion of the bracket 5.

` On the main shaft II of the dial structure which detail as such parts are well known in the'art. 55

rotates 'with the dial 2 is mounted a bracket-I8, and it will be explained hereinafter, how these brackets II, I8 and trigger I3 cooperate. On the main portion of the bracket 5 is mounted, by means of two uprights 2i) and v2 I, two Apermanent magnets 23 and 24 which are placed on opposite sides of a coil 25 which, in turn, is secured by vone of its spoolheads to the permanent magnets 23 andv 24. Inside of this coil 25 is located a vibrating reed 2I which at one end is connected by means of an enlarged portion 28 between the two permanent magnets 23 and 24, while the freefend of this reed 2l is cooperating with the trigger I3 in a manner as will hereinafter be described. At the upper side looking at Fig. 2, is located a pin 3B having a screw 3l which is used as abackstop for the reed 2l when it is tensioned as will be described presently.

The normal positions of the two levers II and I8 and the trigger I3 are shown in Fig. 2. The lever II is normally located so that it will have its projection 35 engage the pin 36 on the leverv I8 to hold the projection 3l on this lever II out of engagementv with the reed 2l and is maintained in this position by the tension of a holding spring 39 which is fastened at one end to the lever lII and at the other end to pin 40 secured to Vthe bracket 5. The lever ES has the angularvprojection II which normally engages the arm 42 of the trigger I3 to hold the trigger arm 43 out of engagement with the reed 2l against the-tension of the spring I5. The operation of Vthe mechanism is as follows: When the operator actuates the dial 2 to send impulses, the lever I8 Will rotate in the counter-clockwise direction looking at Figs. 2, 4 and 5, and thus cause the pin 36 to disengage projection 35 of lever II and permit lever YII to cause its projection 31 to engage the reed ''I. The tension of Spring 39 will thus cause lever II to tension the reed 2l and force it against screw 3l. It will be noted also .that the projection 4I on the lever I 8 will engage itself from the arm 42 of the trigger I3 so as to permit the trigger to be rotated under tension of spring I5 to have its trigger arm 43 enter below or in front of the tensioned reed 21 to prevent this reed fromrreturning to normal or lock it so that it is not free to vibrate under these circumstances. In Fig. 4, the lever I8 has been shown in an advanced position with the lever II and trigger I3 in the position in which the trigger locks the reed in a tensioned position. As is well known the dial on its return to normal will send the usual impulses by operating on the interrupter springs 3. Now, therefore, when the dial returns to normal and immediately after the impulses have been sent and slightly before the dial has returned completely to normal, the

lever I8 will first cause its pin 36 to engage projection 35 on the lever II and return this lever to normal position, thus bringing the projection 31 out of reach of the reed 21. 'Ifhe projection 4I then engagesl the arm v42 on the trigger and returns the triggerto normal position causing the arm 43 to be removed from under the tensioned reed 21 and thus unlocks 'the reed 21 to permit it to vibrate at its natural frequency. Fig. -5 shows the lever II as having been returned to normal position out of reach of the reed 21 and the lever I8 is shown in position lto engage the trigger arm 42 by its projection 4I to remove the arm 43 fromY the reed. This dial structure may be included at a substation as shown in Fig. 7 with the coil 25 connected across the line conductors 50 leading from a substation apparatus 5I toa central office 52 where the line may be associated with a source of current 53, and a suitable means ,54 for-identifying the station.. When therefore .the reed 21 is vibrated at its natural frequency as described above in the electromagnetic field introduced by the permanent magnets 23 and 24, it causes electrical oscillations of a corresponding frequency to be induced` in the coil 25 which then may be transmitted over the line 50 to the central oilice to means 54 where these oscillations may identify the calling line. As an example of the use of the applicants device in connection with a' specific telephone system for identifying calling stations, the copending application by M. E. Mohr, Serial No. 316,903, led on even date with the present application may be mentioned. In this case a party line system has been disclosed in which oscillations produced by dial and reed structures of this or similar types may be employed for identifying calling subscribers by the different frequencies of the oscillations as produced at different stations.

What is claimed is: y

1. In a calling device, an operating member, means responsive to the actuation of said member for producingdifferent series of impulses, a coil, a circuit therefor, a vibratory reed in said coil, means for storing energy in said reed operative in response to the movement of said operating member from normal and for releasing said reed to vibrate at its natural frequencyon the return of said member Vto normal after it has produced a series of impulses to cause oscillations corresponding to said natural frequency to be produced in said circuit. Y

2. In a calling device, a dial, means responsive to the actuation of the dial for producing different series of impulses,'a coil, a circuit therefor, a vibratory reed in said coil, a lever mechanism for tensioning said reed operative in responseto the movementof the dial from normal and for distripping said reed to vibrate at its natural frequency on the return of said dial to normal to cause oscillations corresponding to said natural frequency to be produced in said circuit.

3. In a calling device, an operating member, means responsive to the actuation of said member for producing dilerent series of impulses, a coil,

Ya circuit therefor, a vibratory reed in said coil,

means operative in response to the operation of said operating member from its normal position to tension and lock the reed in a tensioned position and operativein response to the return of the operating member to normal position after it has produced a series of impulses for releasing said reed to vibrate at its natural frequency to produce electrical `oscillations corresponding to said natural frequency'in said circuit.

4. In a calling device, a dial, means responsive to the actuation of the dial for producing differ- -entseries of impulses, a coil, a circuit therefor,

a vibratory reed in said coil, a lever associated with said dial, a lever mechanism, a tripping nger mechanism, said first lever being actuated in response to theY movement of the dial from a normal position to release said lever mechanism to tension the reed and to release said tripping finger mechanism to lock the reed in its tensioned position and being actuated in response to movement of the dial back to the normal position to restore the second lever mechanism andrestore thel tripping finger mechanism to trip the tensioned reed to permit it to vibrate at its natural frequency to produce electrical oscillations corresponding to said natural frequency in said circuit.

5. 'In a calling device, a dial, means responsive to the acuation of the dial for producing different series of impulses, a coil, a circuit therefor, a vibratory reed in said coil, a lever associated withsaid dial, a lever mechanism, a trippingflnger mechanism, said first lever being actuated in response to the movement of the dial from a normal position to release said second lever mechanism to tensionY the reed and to release said tripping finger mechanism to lock the reed in its tensioned position and being actuated in response to the movement of the dial back to the normal position to restore the lever and tripping finger mechanismsrto trip the tensioned reed to permit it to vibrate at its natural frequency to produce electrical oscillations corresponding to said natural frequency in said circuit, said releasing and restoring of the lever and tripping finger mechanisms taking place after the dial has produced a series of impulses.

6. In a calling device, a dial, means responsive to the actuation of the dial for producing different series of impulses, a coil, a circuit therefor, a vibratory reed in said coil, a lever associated with said dial, a second lever, a spring associated with second lever,Y said second lever being held in normal position against the tension of said spring out of engagement with said reed by said rst lever when-the dial is in normal position, a triggernger, a spring associated with said nger, said finger being held in a normal position out of engagement with said reed by said first lever against the tension of said associated spring when the dial is in normal position, said rst lever being kactuated in response to the movement of the dial from a normal position to permit said second lever to move from its normal position under tension of the associatedv spring for tensioning the reed and tov permit said tripping nger to move from its normal position under tension of its associated spring to lock the reed in its tensioned position and being actuated in response to the movement of the dial back to the normal position to restore the second lever to normal against the tension of its associated spring and to restore the tripping lever to normal position against the tension of its associated spring to trip the tensioned reed to permit it to vibrate at its natural frequency to produce electrical oscillations corresponding to said natural frequency in said circuit.

'7. In a calling device, a dial, a coil, a circuit therefor, a vibratory reed in said coil and mechanism for tensioning said reed operative in response to the movement of the dial from normal and for tripping said reed to vibrate in response to the return of the dial to normal to cause oscillations to be produced in said circuit.

8. In a calling device, a dial, a coil, a circuit therefor, a vibrating reed in said coil, permanent magnets associated with said coil and reed, means for energizing said coil, means for tensioning said reed in response to the operation of said dial from normal and for releasing said reed in response to the return of the dial to normal to cause said reed to vibrate in an electromagnetic field introduced by said magnets to cause electrical oscillations to be induced in said coil and transmitted over said circuit.

RUDOLPH F. MALLINA. 

